If you've been reading my blog for a while, you may know that I've been devoted to Nutella for most of my life, so, I felt a little disloyal, for not posting something themed on it, for World Nutella Day (5 February) and decided that today would be the perfect day to make up for it. Being the avid baker I am, I often have shortcrust (sweet and plain), bread dough and sometimes even danish pastry in my freezer. If you're not similarly inclined, by all means use commercial frozen pastry - I have tried it and find it very reliable and virtually indistinguishable from home made; unless you're a deft hand at pastry, it can often be superior.

In keeping with our kitchen philosophy, this is a very easy recipe, with only a handful of ingredients and an end product that is out of proportion to the effort put in. In other words, it's good; very good (though I suppose that is a biased opinion). I hope you agree when you've tried it. If you normally shy away from rolling pins and sheets of waxed paper or plastic (and how could I blame you?) take heart; I sliced pieces from a block of my still frozen pastry, then laid them down like tiles in my baking tray and patted them together to form a pastiche, or quilt, if you will, of pastry. No rolling pin, no grease marks on the counter.

A few tips: try to freeze the pastry lined tin for at least 10 minutes before you put it in the oven. It will ensure that the pastry remains flat instead of blistering and puffing up unattractively, without the added hassle of lining and filling it with beans, real or ceramic, or for that matter, without even needing to prick the pastry with a fork. Second, cool the pastry completely before pouring in the filling and third, stir the filling together just enough to combine everything and chill it before pouring into pastry lined tin. You will be rewarded with a beautiful, crackle topped, perfectly even tart without bumps or sunken craters. One last thing, use a very sharp knife to dice the orange flesh or you will end up with a very wet and ragged mess of orange pulp.

The chocolate flavour is rich, full and pleasantly intense, with the zesty fragrance more than taste, of orange adding a mesmerising nuance. Dark chocolate and orange together, is one of my culinary obsessions and if you like the same combination, I think you will love this. This tart needs very little else to shine - perhaps a fine dusting of icing (confectioner's) sugar, or a dollop of creme fraiche and most certainly, a cup of black, not too sweet coffee.

Slice off even pieces of frozen pastry one at a time and line a 15 cm (6 in) square shallow baking tin, until bottom of tin is covered with an even layer. Press down on edges of cut pieces to close any gaps and form a single layer of pastry. Repeat for the sides of tin.

Put pastry lined tin in freezer for 10 minutes. If you are short of time, bake pastry immediately for 10 minutes or until pale gold.

While pastry bakes, combine eggs, Nutella, orange zest, orange flesh, sugar and chocolate chips. Stir until combined and sugar has more or less dissolved. Do not overmix. Keep mixture in fridge until needed.

When pastry is done, remove from oven and leave until completely cool. Reduce oven temperature to 140 C (280 F)

Remove chocolate mixture from fridge, stir lightly and pour into pastry shell in tin. Smooth top and bake for about 40 minutes or until filling looks set, but jiggles slightly in the middle when shaken gently. Turn off oven, open door slightly and leave tart inside until cold.